The Regional Municipality Of York

ALERT: In response to the COVID-19 situation, York Region has declared a State of Emergency  |  Get the latest on our response to COVID-19  |  Masks and face coverings are mandatory in York Region effective July 17  |  Staying Safe at School during COVID-19


York and Durham Regions release results of 18-month study on strategies to reduce phosphorus from the Duffin Creek Plant

Scientific study underscores historical performance of the Duffin Creek Plant and both Regions’ commitment to a sustainable environment

Newmarket – The Regional Municipality of York and The Regional Municipality of Durham have completed a study requested by the Ministry of the Environment and Climate Change on strategies to further improve the phosphorus discharge from the Duffin Creek Water Pollution Control Plant (Duffin Creek Plant) entering Lake Ontario.

The top-performing Duffin Creek Plant is located on the waters of Lake Ontario in the City of Pickering. It treats wastewater from residents and businesses in most of York Region, plus Ajax and Pickering residents and businesses in Durham Region.

In 2016, York and Durham Regions jointly undertook a Phosphorus Reduction Action Plan study using an international team of leading wastewater treatment experts to research the following:

The level of phosphorus removal the Duffin Creek Plant can achieve with its current wastewater treatment processes (referred to as “secondary treatment”)

The level of phosphorus removal the Duffin Creek Plant can achieve with additional wastewater treatment stages (“tertiary treatment”)

Assess the feasibility of reducing effluent phosphorus during the seasonal algae growth window, April through August of each year

The phosphorus reduction study spanned 18 months and included a peer review by an independent expert in phosphorus removal strategies. The Regions have further confirmed the recommended outcome of the study with a series of tests conducted at the plant over the past 10 months.
Key findings

The Phosphorus Reduction Action Plan reviewed optimization strategies for the existing secondary treatment processes at the plant and a range of potential additional treatment options. The plan recommends proceeding with a strategy to optimize the existing secondary treatment process at the Duffin Creek Plant to achieve lower annual or seasonal average phosphorus concentrations.

The proposed strategy will maintain the Duffin Creek Plant as an environmental leader with the lowest phosphorus discharge limits of any plant discharging to the open waters of Lake Ontario. It is lower than those recommended in the Canada – U.S. Great Lakes Water Quality Agreement and lower than those recommended in the 2017 Draft Action Plan for Lake Erie Phosphorus Reduction.

The proposed strategy to optimize the existing plant processes will have the least impact on greenhouse gas emissions, which remain relatively unchanged, compared to existing plant operations. Strategies to minimize greenhouse gas emissions are a key priority for both Regions.

The Phosphorus Reduction Action Plan concludes plant optimization provides the most sustainable solution when compared with factors including treatment effectiveness, implementation effort and life-cycle costs, as well as environmental benefits associated with greenhouse gas emissions.

York and Durham Regions are proud of the exemplary record of the Duffin Creek Plant as a leader in wastewater treatment. The Regions, along with the provincial and federal governments, have invested more than $850 million over the past 10 years in new technologies, equipment, training and best practices to ensure the Duffin Creek Plant continues to protect our near shore water and local environment.

Results of the Phosphorus Reduction Action Plan are available to the public. Residents are encouraged to view the report and will have until February 23, 2018 to provide any comments or feedback to the Ministry of Environment and Climate Change at:

Ms. Kathleen O’Neill, Director, Environmental Assessment and Permissions Branch
Ministry of the Environment and Climate Change
135 St Clair Ave W, 1st Floor
Toronto, ON M4V 1P5

The Duffin Creek Plant supports the provincial Growth Plan for the Greater Golden Horseshoe, 2006, the York Region Official Plan, 2010 and the Durham Region Official Plan, 2006.

For more information about the Duffin Creek Plant, please visit and

The Regional Municipality of York consists of nine local cities and towns, and provides a variety of programs and services to 1.2 million residents, 51,000 businesses and 600,000 employees. More information about the Region’s key service areas is available at

- 30 -

Media Contact:
Masrine Guthrie-Peart, Corporate Communications, The Regional Municipality of York
Phone:  1-877-464-9675  ext. 77272 or
Cell: 905-251-6416

York Region; Duffin Creek Plant The Regional Municipality of York en-US Media Release